1. Field of the Invention
This invention relates to a floating type industrial borescope for observing the interior of pipings, the bodies and the wings of airplanes, and the like.
2. Description of the Related Art
In a typical borescope, a bending device has been known for bending that flexible tube of the guide tube section which is introduced in the insertion section or enables the insertion section to be guided in an object to be observed. The bending device is constructed such that air cylinders for operating the bending portion of the flexible tube are assembled in the device and wires for bending the bending portion of the flexible tube are connected to pistons in the air cylinders. The wires are pushed or pulled by the air cylinders to bend the bending portion of the flexible tube. An air supplying tube has its distal end connected to each air cylinder and its proximal end to a suction device provided in the operating portion or an air pump. In the air cylinder is mounted a spring member for holding the piston in a predetermined position. At the normal time, i.e., when the flexible tube is not bent, the piston is held in the predetermined position, and the bending portion extends substantially linearly to assume a normal state. The operation of a bending knob provided on the operating section drives the suction device or the air pump to suck the air out of, or supplying the same to the air cylinder through the air supplying tube. This enables the piston to move in the air cylinder and the bending portion of the flexible tube to be bent in cooperation with the movement of the pistons.
With this bending device, since the operating wires are pushed or pulled by the air cylinders to bend only the bending portion of the flexible tube, the overall flexible tube cannot be bent. This poses a problem that the radius of curvature of the bending portion is relatively small.
U.S. Pat. No. 4,735,501 discloses a typical borescope apparatus in which a fluid jet nozzles are provided in the distal end of the cable of a flexible borescope and the cable of the borescope is propelled by the fluid jet ejected from the fluid jet nozzles. It may be possible to bend the flexible tube by the fluid injection from the fluid jet nozzles.
Since the flexible tube is bent by the fluid injection from the fluid jet nozzles, the overall flexible tube can be curved with this borescope apparatus. However, it also encounters a problem that only the distal portion of the flexible tube cannot be bent.